The present invention relates to an analysis system for analyzing a sample on an analytical test element with an optical module.
For the analysis of samples, for example, body fluids such as blood or urine, use is often made of analysis systems in which the samples to be analyzed are located on a test element and react in a test area with one or more reagents on the test element before they are analyzed. Optical, in particular, photometric, as well as electrochemical evaluation of test elements are the most commonly used methods for rapidly determining the concentration of analytes in samples. Analysis systems with test elements for sample analysis are generally used in the field of analytics, environmental analytics, and in particular, in the field of medical diagnostics. In the field of blood glucose diagnostics using capillary blood, test elements which are photometrically or electrochemically evaluated are of great value.
There are various forms of test elements. Essentially square, small plates, also referred to as slides, in the middle of which there is a multilayered test area, are known, for example. Diagnostic test elements of a strip-shaped form are commonly referred to as “test strips.” Test elements are extensively described in the prior art, for example, in the documents DE 19 753 847, EP 0 821 233, EP 0 831 234 or WO 97/02487. The present invention relates to test elements of any form, in particular, to test elements in the form of strips.
For the analytical examination of a sample on a test element, the prior art discloses test element analysis systems which contain a test element holder for positioning the test element in a measuring position and a measuring and evaluation device for carrying out a measurement and determining an analysis result.
WO 00/19185 A1 relates to a device for the photometric evaluation of test elements, comprising an illuminating unit with at least a first and a second light source, a holder for receiving a test element with a detection zone in such a way that the detection zone is positioned with respect to the illuminating unit, a detection unit with at least one detector, which detects light reflected by the detection zone or transmitted through the detection zone, a control unit, which activates the two light sources and records the signal generated by the detection unit as a detection signal, and an evaluation unit, which evaluates the detection signals in order to determine the analyte concentration contained in the sample.
EP 0 618 443 A1 relates to a test strip analysis system comprising an evaluation device with a test strip holder and suitable test strips. The strip holder serves the purpose of positioning the test strip in a defined position with respect to a measuring unit. It has a test strip support and a guide for the test strip.
WO 01/48461 A1 concerns a test element analysis system for the analytical examination of a sample. The analysis system comprises test elements with a supporting film and a test area which is attached to a flat side of the supporting film and, to carry out the analysis, is brought into contact with the sample in such a way that liquid sample constituents penetrate into the test area. The test area contains a reagent system which, when it reacts with constituents of the sample, leads to an optically measurable change in a detection zone that is characteristic of the analysis and which occurs on the side of the test area facing the supporting film. Furthermore, the analysis system comprises an evaluation device with a test element holder for positioning a test element in a measuring position and a measuring device for measuring the optically measurable change in the detection zone, the measuring device having a light transmitter for illuminating the detection zone with primary light and a detector for detecting the secondary light thereby diffusely reflected by the detection zone.
Many such known analysis systems have at least one optical module, which may comprise, inter alia, a lens and a diaphragm, by which the light can be focused. These optical modules are produced in the prior art from a number of individual parts, which are put together and connected to one another, for example, by means of ultrasonic welding, hot caulking or adhesive bonding. When doing so, the lens and the diaphragm aperture must be spatially positioned exactly in relation to one another in a way corresponding to the path of rays of the light. The joining together of the parts is only possible with great effort due to their tolerances and small size. Furthermore, having many individual parts necessitates a strict overall tolerance of the optical module.